1. Technical Field
This invention relates to multiple port valves particularly useful in controlling coolant supply and return lines associated with electrical resistant welding apparatus wherein the coolant liquid must be discontinued when the welding tips are replaced.
2. Description of the Prior Art
No specific prior art is known wherein a cylindrical valve member in a cylindrical bore in a valve body is provided with transverse passageways registrable with inlet and outlet openings whereby coolant fluid supply and return lines may be simultaneously closed and/or opened and wherein compressed resilient elastic rubber plugs in the cylindrical valve member circumferentially spaced with respect to the transverse passageways are movable into an expanded sealing relation with said inlet and outlet ports when the cylindrical valve member is rotated on its longitudinal axis.
U.S. Pat. Nos. 1,681,394, 2,088,632, 2,154,945, 2,663,315, 3,530,892, 2,868,499, and French Pat. No. 1,452,637 all disclose valve structures in which rotatable cylindrical valve members are employed. None of the patents disclose the use of compressed resilient elastic rubber plugs mounted in a cylindrical valve body so as to be movable into expanded engagement with oppositely disposed inlet and outlet ports to positively seal the same. Metal to metal surfaces of rotatable valve members and inlet and outlet ports are seen in U.S. Pat. No. 1,681,394, cut-away areas of a cylindrical valve member are seen in U.S. Pat. No. 2,088,632 substantially transverse passageways in a rotatable valve member are seen in U.S. Pat. Nos. 2,154,945 and 2,663,315. In U.S. Pat. No. 3,530,892 define a plunger having axial bore therein in a passageway communicating with the actual bore, spring means are used to urge the plunger towards the cylindrical valve element. The device is arranged to provide a gas-tight communication between between the passageway in the cylindrical valve member and the port in which the plunger is mounted. Patent 2,868,499 discloses a plug type valve having bearing elements extending beyond the surface of the valve element in a constant fixed relation and French Pat. No. 1,452,634 discloses a multiple port valve design utilizing a pair of oppositely disposed O-rings to seal around each aligned port of the metal valve element.
The present invention provides the novel highly efficient compressed resilient elastic rubber plugs in a cylindrical valve member positioned for registry with the ports, the plugs being so formed as to bulge into the ports after effectively wiping the same when the valve element is moved to a closed position due to their oversize relationship in relation to the ports and their mounting cavity.